Interchangeable porcelain root facing



April 25, 1933. A s, LEVY INTERGHANGEABLE PORCELAIN ROOT FACING FiledAug. 28, 1922 Patented Apr. 25, 1933 Uira ARTHUR S. LEVY, OF BIRMINGHAM,ALABAMA, ASSIGNOR, BY MESNE ASSIGNMENTSQ TO DIXIE DENTALFIANUFACTURIIQG'OO O1 'EHILADELPEIA, PENNSYLVANIA, A

COREORATION OF PENNSYLVANIA INTERCEAHGEABLE FGECELAI'X RGO)? FACINGApplication filed August 28, 19532. Serial No. 524,729.

My invention relates to an integral porcelain facing and root extensionpreferably having an interchangeable attachment for connecting it to acusp to form a novel artificial dummy tooth andto a processfor mountingsuch an artificial tooth with its root extension embedded in the gum oralveolar process. V

The most modern dental practice indicates the desirability of utilizinga dummy toot-h having a porcelain root which will enter to sive andrequires equipment and skill beyond the ordinary, as high pressure isnec essary to obtain a perfectly smooth surface which is essential inthe case of any part in! tended to enter the gum and alveolar process.

After the combined facing and root have been thus produced, somefeasible fastening must be-provided for its connection to the cusp,which, in the manner well understood'in this art, can then be mounted inthe bridge or connected to the adjacent tooth abutments. Obviously, whenso mounted in the mouth, the cusp attachment is permanent and anyfracture or damage tothe facing requires a most expensive operation todismount the dummy or bridge, repair the injured or bro,-v

ken part and then remount the dummy in the mouth.

One object of my invention is to adapt the integral porcelain facing androot extension to be manufactured and sold to the trade as an integralinterchangeable root facing in the requisite standard shapes and colorsand equipped with suitable interchangeable fastenings, backings orcusps, thus enabling the local dentist to select an appropriate facinghaving the desired type of root extension, then grind the occlusal endof the facing to fit the case in hand, and then select a ready made cuspto fit the ground facing, thus forming a dummy without a baking, castingor soldering operating and by thisme ans the desirable practice of usingdummies with a .root extension can be greatly enlarged.

A further object is to so design the combined facing and root extension,with relation to its interchangeable fastening, that when any part ofthe porcelain facingis brokenor damaged and needs to be replaced, it canbe removed and replaced without dis turbing the mounting of the cusp.This I. accomplish by inclining labio-bucco occlusally the co-actinginterchangeable fastening elements of backing and root facing anddisposing in substantial parallelism with the line of inclination ofsuch fastening that por .tion of the surface of the root extension whichis in contact with the gum tissue and, which must move outwardly oversuch tissue as the root facing is removed forrepair' or interchange. Inother words the root portion of the facing shall be so designed thatnotwithstanding it has portions which over-i lap parts of the gum on thelingual side there- 'of, nevertheless such portions ofthe root ex?tension will, in following the line of inclination ofthe fastening, rideoverlthe gum without injury thereto. When I refer to the gum above Imean to includelany portion thereof which it .may be desired to have theroot extension engage. By such an arrange ment notwithstanding that theroot extension is embedded in the alveolar process the root extensionand facing as a whole can be slippedoff the fastening as it is movedoutwardly between the approximately parallel, surfaces of the cusp baseand outer wall of the socket inthe gum and bony process.

A further feature of my invention is to so design and arrange theinterchangeable attachment that all the necessary grinding of the facingto fit must be done at its occlusal, rather than a its gingival end, ashas heretofore been the case, as the latter end must be left with asmooth porcelain surface if a, rebaking of the root facing is'to beavoided.

The following important advantages accrue from this feature, i. e., eachsize of root fac ing can be ground to fit a greater variety of caseswithout weakening the attachment be: tween the root extension and cuspand the number of molds required for the production of the root facingscan be reduced to a minimum, and it forms the root extension of smoothglazed porcelain which alone is suitable to enter or even engage thegum, hence my invention has within its Contemplation the formation withthe facing proper of a root extension formed of a heavy glazed ungroundbody of porcelain which alone contacts with the gum whether to merelyengage or to penetrate same, and which is shaped so that the jointbetween it and the cusp is not in contact with the gum or bony process.

My invention in its preferred embodiment is illustrated in theaccompanying drawing which shows several styles of interchangeablefastenings.

Fig.1 is a side elevation of a dummy shown with its root extensionseated in a tooth socket in the bony process.

Fig. 2 is a detail cross-sectional View of the combined facing and root,as shown in Fig. 1, the dotted line indicating the path followed by thefacing in removing it from its permanently anchored cusp or backing.Fig. 3 is an elevation of the facing and root extension shown in Fig. 2.

Fig. 4 is a vertical cross-sectional view of a dummy having a modifiedtype of interchangeable mounting for the root facing.

Figs. 5 and 6 are views corresponding in perspective, showing in Fig. 5the complete dummy mounted in the mouth, and in Fig. 6 the cusp orbacking as same would appear after the removal of the root facing.

Similar reference numerals refer to similar parts throughout thedrawing.

As illustrated, the dummy tooth comprises a porcelain with a rootextension 1 preferably formed integrally with the facing 2, and the rootextension being provided on its upper surface with a cusp or backingseat 3 which slopes upwardly or downwardly according to the position ofthe facing in the upper or lower jaw towards and joins the back wall 4of the facing 2. The root seat 3 is disposed so as to be out of contactwith the gum or alveolarprocess and'preferably has formed therein anundercut slot 5 which extends from the gingival end of the seat 3substantially to the base of the back wall 4,

the undercut portion of the slot being preferably extended at 6 into thefacing 2. Such an undercut slot can be formed in accordance with thegeneral practice in this art and it is adapted to receive aninterchangeable fastening pin 7 which has a shank 8 that is embedded inthe cusp or backing 9 of the dummy 2. This pin is of well knownconstruction and will fit snugly in the slot 5 with an extension fittinginto the extension 6 of the slot,-

and it will serve to detachably mount the root facing on the cusp orbacking. This cusp or backing is fitted to the lingual faces of the rootfacing having faces 3 and 4 which respectively engage the faces 3 and atof the root facing and when attached thereto forms a complete dummy,which by means of anchors or abutment-s 10 can be anchored to theabutment teeth 11, which are typical of any anchorage means for thebacking in the natural teeth or in an artificial bridge. If desired theshank 8 of the interchangeable fastening pin 7 may be anchored intheroot extension 1 so as to dispose the pin 7 parallel with and spacedslightly above the root xtension seat 3. The upper end of the pin 7 ispreferably baked in the facing 2. The pin stops short of the rear edgeof the seat 3. The cusp or backing 9 is formed of gold about the pinwhich thus serves as an interchangeable fastening to connect the rootfacing to the cusp or backing.

In practice, the dentist grinds the occlusal end of the facing 2 to thesize required and the cusp is either selected from stock or molded andcemented in place in the manner well understood in the art. By thismeans a dummy-tooth with a root extension can be produced anddistributed to the trade as a complete article of manufacture anddummies with porcelain root extensions can be produced at comparativelysmall cost, thus permitting their wide spread use.

Having mounted the dummy by the attachment of'the cusp'tothe adjacentabutments or bridge, if the facing or root is broken or damaged it willbe found, by observing the corresponding inclination of the seat 3 withthe inclination of the outer root extension wall engaged in. the rootsocket in the bony process 13, that'the combination porcelain v rootfacing as a whole can be detached bv being moved upwardly along the pathindicated by'the dotted lines between Figs. 1 and 2, and thus slippedoutwardly off the pin 7, which movement will at the same time cause theroot extension to rise out of the socket'and thus allow its disengagemnt without destroying the cusp mounting and permit a new root facing tobe remounted on the same cusp.

I desire to claim this feature broadly and without reference to anyparticular style of attachment or method of manufacture of the rootfacing.

In Fig. 1 I show a cross section of the jaw 13 with the socket 141 leftby the extraction of the natural tooth filled with bone building cells15 except for the portion thereof occu pied by the root extension 1which goes far enough into the socket to hold the inner and outer plates16'and 17 of the bony process substantially in their original position.It will be seen that the bone cells 15 will fill in all around the rootextension 1 and that the gum 18 hugs it as tightly as it would thenatural tooth.

The advantages of my invention briefly stated, are

1. Absorption of the bony process is lessened to a great extent byholding the outer and inner plates 16 and 17 in position, thuspreserving the natural facial expression.

2. The natural outline of the lost tooth is carried out as far aspossible, which adds to the comfort of the patient, protects theunderlying tissues, preserves the articulation of speech, and eliminatesa V-shaped space which in the present practice is left between thebacking on the one hand and the gum 18 on the other, such spaceproviding an undesirable pocket for the collection of food particles.

3. Highly glazed porcelain when placed in the mouth remains cleaner thanany material known today, hence a bridge composed of a root facing withthe porcelain root extension engaging or embedded in the gum is the mostsanitary that can be made.

4. Inasmuch as the root facing is to be made in its preferred form as anintegral porcelain element, there will be no joint or crack between thefacing and the root extension and the whole will present to the gum orbony process only a'highly glazed, smooth un interrupted surface whichalone is obtainable where the tooth is baked under heavy pressure, andthe joint with the backing or cusp is kept away from the gum.

5'. Due to the fact that the root extension goes directly into the toothsocket and that as result there will be but little absorption of thebony process, it will not be necessary to remove the root facing inaccordance with my'invention and replace it with a longer one.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent, is

1. As an article of manufacture, a porcelain root and facing, the rootportion having at its occlusal end a cusp seat inclined labiobucco,occlusally to correspond with the slope of the diametrically oppositeface of the root portion that is to be embedded in the tooth socket, anda. pin fastening'slot in the root disposed parallel with said seat andface.

2. The divisible tooth which includes a tooth body having its crownportion intersected by a dovetailed mortise which extends through therear surface of the tooth-body and thence forward to its terminus at adistance from the front surface of the tooth, the front part of saidcrown portion being a greater distance than its rear part from thegingival end of the tooth, and a cusp plate having a surface to fit onsaid crown portion; said cusp plate having a tenon which has across-section conforming to that of said mortise so as to be slidableinto and out of the mortise.

tion but terminating short of the length of v the labial portion, thebottom face of said downwardly:- extending iportion and the lingual faceof the labial portion constituting ;planes intersectingiman-obtusezangle, a bore in and extendingitransversely through :thedownwardlyextending portion {and 1 opening I into-the lingualfacerof-thesaidiportion, a slot of -less diameten opening rsaid bore' tothe plane of the -llI1ClIlfaCQ of .said downwardly V extending,portionand a backing formed to coveri said planes'and provided with .a tenon 1comple nental to the bore-and slot. V

I 4. Atoothwhich includes a root extension and; acrown portion, thecrownportion ,pro- .vided :with :zan inclined surface extending labioocclusallyr from the ,lingual side, the lfront side beingga greaterdistance than the rear sidefromthegingivalend of \the (tooth; ametalbacking having a surface to rfitrsaid incline-d --surface; :saidcrown";portion and backing having retaining means disposed :in thedirection-- of the iin'clined; surface rilIlCltellgage'd by a relativesliding inovementxofthe incli ned surfaces -o1fthe crown portion and.the backing, whereby the root extension can be withdrawn from the :rootsocket by an 3&0 out-ward :movement 'in -the;directionfzof said inclinedsurface. 7 t Y 5. A- divisible toot-h including a tooth body:-and a cuspplate,"the tooth body being formed wit-hart integral moot-extension, abacking seat formed on said tooth-body,.-said seat- "being disposed soiasvto -betout -o'f;contact with theagum' a'; bore :in ithe tooth lbodyle-x tending :fromqthe lingual face toward the "labial lfac'e; -f-a slot(of less, diameter opening @400 said bore. forxa ipartof -.its-;lengthto-.the surface 'of said :seat,-ithe 7 remaining portion :of thebore-.being1closed-:to'-said&seat,and1divergent to thepart 50fthe-surface beyond the end 0f 'tl16 slot,wsaid ct 1sp plate havinga postconnected; tozit; by --a plate of less diameter than the ;post wherebytherpost and plate are adaptedtorslidelandfit -:in.-saidlbor.e; and slotand :thereby connect the acusp plate :to the tooth body,"-.therlabialend portionl-of the :post

extending into the; toothabodywbeyon-d :the labialfend ofthaslot; 1 ii6,--llhe,di-vi-sible teeth which includes .a tooth-body having itscrown ,portionaintersecteda mortise which-extends ztlrrough theilinguals face of-atheitooth-body and thence forward to its terminus ata distance from the labial face of the tooth, the labial face of saidtooth extending a greater distance than its lingual. face from thegingival end of the tooth; and a cusp plate having a surface to fit onsaid crown portion, said cusp plate having a tenon conforming to that ofsaid mortise so as to be slidable into and out of the mortise.

7 An artificial tooth comprising a facing, a root and a lingual overhangportion, a post hole extending from the lingual side into the overhangportion and a slot in the under face of the overhang portioncommunicating ginigiyl'al'ly throughout its length with said post 10 e.V 1 8. In permanent dental bridgework, a pontic structure for permanentattachment in the mouth and presenting a cusp opposite a tooth gap withan occlusal surface formed on said cusp, the gingival surface of saidcusp having an inclinedlabio-occlusally from the lingual side, aporcelain tooth-body hav' ing a facing and an integral root extensionadapted to be received within the socket left by extraction of thenatural tooth prior to absorption of the bony process, said root exetension having an inclined occlusal surface adapted to fit said inclinedgingival surface of said Cusp, and interlocking elements on the saidcuspand said body'whereby said body may he slidinto engagement with said M icusp in the direction of said inclined surfaces 2 and thereby into saidsocket. 4 I

9. An artificial tooth which includes a root extension and a crownportion, the tooth body being provided With-an inclined sur- M faceextending labio-occlusally from the lingual face, and a mortiseextending through the lingual face of the tooth, the labial face of thetooth extending a greater distance than the lingual f-ace from thegingiv-al end, and a cusp plate having'a urface to fit said incline-dsurface, and tenon to Cooperate with the mortise. r 10. A divisibletooth including a tooth 7 body and a cusp plate, the tooth body beingformed with an integral root extension, a backing seat formed onsaid'tooth body, said seat being disposed so as'to be out of contact with thegum, a bore in the tooth body extending from tlielingual face toward thei labial face, a slot of less diameter opening 40 said bore for a partof its length to the surface of said'seat, the remaining portion of thebore being closed to said'seat, said cusp plate having a post connectedto it'by a plate of less diameter than the post'whereby the post andplate are adapted to slide and fit in said bore and slot and therebyconnect the cusp plate to the tooth body, the labial end portion of thepost extending beyond the labial end of the slot. In'testimony whereof Iaffix m signature.

' I ARTHUR LEVY.

CERTIFICATE OF CORRECTION Patent No. 1,905,595. April 25, 19

ARTHUR s. LEVY.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page Lline 8, claim 8, for the word "inclined" read incline; and that the saidLetters Patent shouldbe read with this correction therein that the samemay conform to the record of the case in the Patent Offioe. M

Signed and sealed this 8th day of February, A. D. 19

5 Henry Van Arsdale, (Seal) Acting Commissioner of Patents.

